宾语从句什么时候要用it（形式宾语）如I appreciate it if……

宾语从句什么时候要用it（形式宾语）如I appreciate it if……

形式宾语it代替的宾语从句 ①动词find,feel,consider,make,believe等后面有宾语补足语的时候，则需要用it做形式宾语而将that宾语从句后置.
例句：
I think it necessary that we take plenty of hot water every day .
我认为每天多喝开水是有必要的.
I feel it a pity that I haven’t been to the get-together.
我没去聚会，感觉非常遗憾.
I have made it a rule that I keep diaries.
我每天写日记成了习惯.
We all find it important that we (should) make a quick decision about this mater.
我们都认为对这件事马上做出决定很重要.
②有些动词带宾语从句时寻要在宾语与从句前加it
这类动词主要有：hate,take,owe,have,seeto.
例句：
I hate it when they with their mouths full of food.
我讨厌他们满嘴食物时说话.
He will have it that our plan is really practical.
他会认为我们的计划确实可行.
We take it that you will agree with us.
我们认为你会同意我们的.
When you start the engine,you must see to it that car is in neutral.
开启发动机时，一定要使汽车的离合器处于空挡位置.
③若宾语从句是wh-类，则不可用it代替
例句：
We all consider what you said to be unbelievable.
我们都认为你所说的是不可信的.
We discovered what we had learned to be valuable.
我们发现我们所学到的东西都是有用的.

①宾语从句+宾语补足语的结构为了保持句子平衡，常用it作形式宾语,把真正的宾语从句置于句末，常见的it作形式宾语的谓语动词有believe,find,make,guess,suppose等。 he didn't make it clear when and where the meeting would be held. ②某些及物动词或短语不能直接加宾语从句，此时用it作形式宾语，然后再接宾语从句，此种用法常见于like,dislike,hate,appreciate等。 i'd appreciate it if you would like to teach me how to use the computer.